Food packaging process



T. C. BOMAR ETAL FOOD PACKAGING PROCESS Jan. 30, 1968 5 Sheets-Sheet 1Filed July, 29, 1965 INVENTOR. 77/0/7/15 6. HUGH/3 50/44? .70/9/1/60/1/W/L L /A M 5. MC 00444.40

Jan. 30, 1968 T. c. BOMAR ETAL 3,366,496

FOOD PACKAGING PROCES S 5 Sheets-Sheet 2 Filed July 29, 1965 FIG.5

INVENTOR. 7/70/7145 6' 50/7/09 HUGH B. JOHNSON WILL /AM 5 Mc DON/1L0 5)v Jan. 30, 1968 T. c. BOMAR ETAL 3,366,496 FOOD PACKAGING PROCESS FiledJuly 29, 1965 3' Sheets-$het s 1FOIG.IO

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INVENTOR. 7/9 0/1/15 a emu/P HUG 1 8. JOH/VJO/V WILL/AM 5. NC 004 4410ATTO/PA/E) United States Patent 3,366,496 FOOD PACKAGING PROCESS ThomasC. Bornar, Wiiliarn S. McDonald, and Hugh B.

Johnson, Georgetown, S.C., assignors to International Paper Company, NewYork, N.Y., a corporation of New York Filed July 29, 1965, Ser. No.475,786 4 Ciaims. (Cl. 99-198) This invention relates to containers and,more particularly, to containers made of corrugated paperboard forpackaging perishable foods, such as fruits or vegetables.

Fruits, such as peaches, are picked in the summer and it is necessary tocool them as quickly as possible to remove field heat and to preventspoilage. A known method for accomplishing this is hydrocooling; thatis, cooling by use of water.

The present invention is of particular significance in the packaging ofperishable foods which have been hydrocooled prior to storage andshipment.

In one form of hydrocooling employed in the peach industry, the peachesare packed, in bulk, in open-top containers and subjected to a coldwater shower. The water circulates around the peaches to cool them anddrains through openings in the containers and into a water collectiontrough where it is recirculated back into the cooling system. After thepeaches are cooled sufiiciently, the tops are placed on the containers,which are stacked one atop the other on pallets and placed in highhumidity refrigeration rooms to await shipment.

Since moisture is known to adversely affect the strength of corrugatedpaperboard, it has been the general practice to use wooden containers orwood-wirebound crates in packaging peaches under the conditions justdescribed, in spite of their expense and attendant dimculties inhandling.

It is, therefore, a principal object of this invention to provide acontainer formed of corrugated paperboard which is capable of use in thepackaging of perishable foods under moist or humid conditions.

It has been found that particular attention must be paid to the choiceof components (liners and medium) which are to comprise the corrugatedpaperboard of the present invention and to the method of making suchcorrugated paperboard.

Preferably, the liners are formed from wet-strength linerboard,available commercially under the trademarks Hydro Kraft and Gator Pak,owned by International Paper Company, and the corrugating medium isformed from wet-strength paperboard, available commercially under thetrademarks Hydro-Chem and Weathertex, also owned by International PaperCompany.

A preferred method of making the corrugated paperboard of this inventionincludes the steps of treating the corrugating medium with wax or a waxblend prior to corrugating, and treating the liners with wax or a waxblend either prior or subsequent to the securing of the liners to thecorrugated medium.

The wax or wax blend used to treat the liners should be of a refinedquality suitable for use in contact with foods and it is applied withparticular regard respecting its temperature and point of application soas to obtain liners capable of use in the packaging of foods under Wet,moist, or humid conditions.

The corrugating medium is treated with wax or a molten blend of waxesand thermoplastic resins or thermoplastic resins alone prior tocorrugating, using critical temperatures and moisture treatment ortreatments so as to obtain a corrugated medium capable of use in thepackaging of foods under wet, moist, or humid conditions.

The container blanks of the present invention may be formed from thecorrugated paperboard of the invention by well-known means and withstandard equipment.

3,3hh,4% Patented Jan. 30, 1968 It is preferred that the flutes of thecorrugated medium in the blanks and in the containers formed from theblanks should be disposed predominantly longitudinally of the blanks toassure that the minimum number of flute openings will be disposed toaccept debilitating water.

More specifically, the containers of this invention are comprised of abody and a cover which can readily be secured or locked to the body as afinal step of a method of packaging perishable foods which have beenhydrocooled in the body. The containers are provided with reinforcedparts to give them stacking strength, simple fastening means by whichthey are secured erect, eflicient and non-contaminating drainage means,and locking means to lock the cover to the body.

A further object of this invention is to provide a corrugated paperboardcontainer having excellent drainage and good stacking strength.

A further object is to provide a corrugated paperboard container capableof withstanding a cold water shower and the rigors of storage andshipment.

Another further object is to provide a container formed of corrugatedpaperboard having high resistance to water.

Another object is to provide a container which is formed from a fiatone-piece blank which is simple in construction and economical tomanufacture.

Another object is to provide a corrugated paperboard container in whicha minimum number of flute openings are disposed to accept debilitatingwater.

And, another object is to provide a container cover formed of corrugatedpaperboard and having a high resistance to water.

Other objects and advantages Will become apparent from the followingspecification, claims, and drawings, in which:

FIG. 1 is a plan view of a blank from which a container body of thepresent invention is made;

FIG. 2 is a plan View of a blank from which a container cover of thepresent invention is made;

FIG. 3 is a perspective view (with parts broken away) showing a stage offolding the blank of FIG. 1;

FIG. 4 is a perspective view (with parts broken away) showing a stage offolding the blank of FIG. 1;

FIG. 5 is a perspective view (with parts broken away) showing a stage offolding the blank of FIG. 1;

FIG. 6 is a perspective view (with parts broken away) showing a stage offolding the blank of FIG. 1;

FIG. 7 is a perspective view (with parts broken away) showing a stage offolding the blank of FIG. 1;

FIG. 8 is an exploded perspective view showing the assembled containercover and container body;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 8; and,

FIG. 10 is a sectional view taken along line 1010 of FIG. 8.

The container 106, as seen in FIGS. 8, 9, and 10, comprises a body Bformed from a blank 1 (FIG. 1), and a cover C, formed from a blank 30(FIG. 2).

The blanks 1 and 30 are formed from corrugated paperboard which consistsof a corrugated medium 101 sandwiched between an inner liner 102 andouter liner 163. The orientation of the flutes of the corrugated medium101 is predominately longitudinal of the blank, for reasons to befurther explained.

The blank 1 for forming the body B has horizontal fold lines 2, verticalfold lines 3, and slots 4 which define and hingedly connect a bottom 5(including first and second bottom panels 6 and 7), side walls 8(including first and second side wall panels 9 and 10), end walls 11(including first, second and third end wall panels 12, 13, and 14), andan attaching flap 15 for forming a manufacturers joint when forming theblank into a container body.

The bottom panels, the side wall panels, and the end wall panels areprovided with means defining water drainage openings 16, in the form ofelongated cut-outs 17, in the form of circular cut-outs 18, and in theform of semicircular cut-outs 19. The first and second end wall panels12 and 13 are each further provided with means defining a hand-hold 20,in the form of an elongated cut-out 21, and with means defining a coverlocking aperture 22, in the form of an elongated cutout 23 and thehorizontal fold lines 2a and 2b define stacking ledge panels 24therebetween, all for purposes to be described.

The blank 30 for forming the cover C has horizontal fold lines 31,vertical fold lines 32, and slots 34 which define and hingedly connect atop panel 35, side walls 36, and end walls 37 (including first, second,and third end wall panels 38, 39, and 40).

The blank 30 is further provided with means defining a pluraltiy ofconnecting flaps 41, in the form of arcuate slits 42 extendingsubstantially from intersections of the horizontal and vertical foldlines 31 and 32, and each of such connecting flaps is provided withmeans defining a cover locking aperture 43, in the form of asubstantially rectangular cut-out 45. The third end wall panels 40 areeach cut away, as at 46, to define cover locking tabs 47 and a bodylocking tab 48; the top panel 35 is provided with means defining a waterdrainage opening 49, in the form of a circular cut-out 50, and the foldlines 32a define a hand-hold ledge 51 therebetween, all for purposes tobe described. 1

To form the body B from the blank 1 of FIG. 1, the side panels 9 and theend panels 12 are folded perpendicularly to each other and to theattaching flap 15 which is folded into abutting contact with one of theend panels 12 where it is secured by glue or staples to form amanufacturers joint. The bottom panel 6 is folded into temporary contactwith one of the side panels 9 and the end panels 13 are folded intoabutting contact with the bottom panel 7 and together these parts arefolded perpendicularly to the other side panel 9, after which the endpanels 13 are folded into abutting contact with the end panels 12 andthe bottom panel 6 is folded into abutting contact with the bottom panel7. The side panels and the end panels 14 are then folded into abuttingcontact with the side panels 9 and the end panels 13, respectively.Friction holds the parts, thus folded, in their respective positions.

To form the cover C from the blank 30 of FIG. 2, the side wall panels 36are folded perpendicularly to the top panel 35 and the second end wallpanels 39 are folded perpendicularly to the panels 36 thus bringing theconnecting flaps into abutting contact with the lower surface of the toppanel 35 at the four corners thereof. The first and third end wallpanels 38 and 40 are folded perpendicularly to the top panel 35 andaround the second end wall panels 39 and the cover locking tabs 47 areinserted in the cover locking apertures 43 in connecting flaps 41 tolock the parts in place, as shown most clearly in FIG. 8.

In the hydrocoolirig method of this invention, freshly picked peachesare packed, in bulk, within the body B and subjected to a cold watershower. The water drains through the mated water drainage openings 16 inthe bottom, side, and end wall panels and into a collection trough to berecirculated back into the cooling system. The cover C is thenpositioned on and secured to the body B by inserting the body lockingtabs 48 into the cover locking apertures 22, as shown in FIG. 9.

It will be noted that the flute openings of the corrugated paperboard ofthe cover C and the body B of the container are minimally exposed todebilitating water to further enhance the containers utility in thehydrocooling operation.

It is also important to observe that, aside from the single drainageopening 49, the top panel 35 of the cover C has no water access openingsin it. This is so in spite of the fact that the cover is capable ofassembly without the use of extraneous means. Such assembly isaccomplished by simply inserting the locking tabs 47 into the lockingaperture 43 in the connecting flaps 41, which are positioned below andin abutting contact with the undersurface of the top panel 35 at itsfour corners, thereby obviating the necessity of forming such aperturesin the top panel itself at the corners thereof, as is commonly done.

It will be noted that the end walls 11 of container are of triplethickness; that the side walls 8 are of double thickness; and, that thebottom 5 is of double thickness. The thicknesses of the end and sidewalls give the container considerable stacking strength and thethicknesses of the bottom help retard heat pick-up after cooling.

It is further important to observe that the plurality of thicknesses ofthe end and side walls and the bottom provide a container of exceptionalstrength and it is within the scope of this invention to provide for theelimination of all openings 16 in the end and side walls and in thebottom and for the elimination of the opening 49 in the top panel 35 ofthe cover C and to thereby provide a container of exceptional strengthfor packaging articles in a dry state.

To lift the container, the user need merely to insert his fingers in thehand-holes 20 in the first and second end wall panels 12 and 13 and liftit, in a manner well known in the art. Since there are no hand-holes inthe third end wall panels 14, the users fingers do not contact the fruitinside the container; thus bruising is eliminated.

As has been previously stated, the specific corrugated paperboard usedin the container and the method of making such paperboard are ofparamount importance in the practice of the invention. Specifically, thepaperboard must be capable of use in an environment of severeatmospheric conditions of wetness and humidity, which normally wouldtend to deteriorate the paperboard.

A preferred method of making the corrugated papera board of thisinvention comprises the steps of (1) treating the corrugating mediumwith wax or a wax blend prior to corrugating, (2) corrugating thetreated medium, (3) securing the corrugated medium to inner and outerliners, and (4) treating the liners with wax or a wax blend. 7

In accordance with this invention, the material used in the container ispreferably wet-strength paperboard. If desired, the paperboard may betreated by adding wet strength resins to the paper pulp at the heaterand before the paperboard sheet is formed on the paper machine.

The corrugating medium is treated with wax or a wax blend, further to bedescribed, preferably in molten form and ordinarily in an amountapproximating 25 to 30% of the weight of the paper.

The corrugating medium is moisture conditioned by subjecting it to awater mist or spray prior to applying the wax blend by immersion orotherwise.

The treated medium is immediately thereafter subjected to furthermoisture and temperature conditioning by means of water mists, heaters,and steam applicators, all prior to being fed to the corrugating rolls.

Moisture and temperature conditioning are vital to the treatment of thecorrugating medium. It has been found that these treatments enlarge theinterstices of the sheet making it more receptive to the proper adhesionpenetration necessary for adequate bonding. Further, an optimum moisturecontent improves the forming characteristic of the medium therebyminimizing the types of malformation possible during corrugating, and italso permits the use of conventional water system adhesives.

The paperboard is then corrugated by means of a set of corrugatingrolls. During this operation, it is advisable to have the corrugatingmedium at a relatively high temperature.

After the corrugating operation is completed, a suitable adhesive isapplied to the crests of the corrugations of the corrugated medium andone of the liners is pressed against the medium at the single-facer andheld in place until it is secured thereto. Adhesive is then applied tothe crests of the corrugations on the other side of the medium and theother liner is combined to it at the double-facer or double-backer.

The combined double-faced corrugated board then passes through thecorrugator. The process has the advantage of being able to impregnatethe medium and liners separately and with different formulations,blends, and quantities.

The invention may be employed on corrugating lines running at normalproduction rates of about 175 to 300 or 400 feet per minute. Thestandard weights of webs may be used but it is preferred to use 26, 30,33 or 36 pounds per 1000 square feet (before corrugation) for thecorrugated medium and 26, 33, 38, 42, 47, 69 or 90 pounds per 1000square feet for the liners.

It has been found that the performance of the corrugated paperboard canbe further improved by surface coating, preferably with hot melt waxblends. This is, of course, desirable in applications Where externalwater is the primary hazard, such as in hydrocooling operations. Theboard is preferably printed prior to the surface coating operation.

It is preferred to wax the liners at one or more waxing stations afterthe belt. Typically, the first station consists of two driven and heatedrolls and the second station of two driven rubber rolls. The advantageof positioning the rolls past the belt is that by so doing the belt isnot exposed to wax and, therefore, there is no danger of wax build-up.

The combined board is subjected to the wax showers beyond the corrugatorbelt, thus avoiding wax build-up on the belt.

The wax blend is applied in amounts approximating to 40% of the weightof the paper, and is heated from 225 F. to 300 F. depending on boardgrade and type and applied by rollers to the board. A wicking actionoccurs.

The wax blend which is employed preferably consists of a blend of waxesand petroleum resin polymers and copolymers with the wax totaling from60% to 95% of the mixture. Approximately to addition based on the weightof the paper gives the best results. Beyond 30% the synergistic effectappears to diminish and the performance gained is not commensurate tothe added cost.

The adhesive mixture which is employed is preferably of the aqueoustype, starch or starch-resin combination.

The preferred method of applying the wax blend is inline on thecorrugator thereby taking advantage of the heat generated by thecorrugator. Wax continues to migrate during and after bonding due to theheat of the corrugator.

What is claimed is:

1. In the manufacture of corrugated paperboard consisting of acorrugated medium sandwiched between an inner and an outer liner andadapted to be converted into packaging, a process comprising the step ofapplying wax or a blend of wax and thermoplastic resin to thecorrugating medium prior to corrugating, the step of corrugating thecorrugating medium, the step of applying an adhesive formulation betweenthe liners and the corrugated medium, and the step of bonding the linersand corrugated medium together with heat and pressure, wherein thecorrugating medium is moisture conditioned before and after the wax orblend of wax and thermoplastic resin is applied to it.

2. A packaging process for packaging perishable foods in a container,said container being formed of corrugated paperboard consisting of acorrugated medium sandwiched between an inner and an outer liner andmade in accordance with the process of claim 1, said container havingparts including a bottom, side walls, and end walls and means definingwater drainage openings therein, said packaging process includingpacking said foods in bulk within the container, subjecting the foodspositioned within the container to a cold water shower, allowing thewater to drain through the openings in the container body.

3. In the manufacture of corrugated paperboard consisting of acorrugated medium sandwiched between an inner and outer liner adapted tobe converted into packaging, and a process comprising the step ofapplying wax or a blend of Wax and thermoplastic resin to thecorrugating medium prior to corrugating, the step of corrugating thecorrugating medium, the step of applying an adhesive formulation betweenthe liners and the corrugated medium, the step of bonding the liners andcorrugating medium together with heat and pressure, and the step ofapplying wax or a blend of wax and thermoplastic resin to at least oneof the liners, wherein the corrugating medium is moisture conditionedbefore and after the wax or blend of wax and thermoplastic resin isapplied to it.

4. In the manufacture of corrugated paperboard consisting of acorrugated medium sandwiched between an inner and outer liner adapted tobe converted into packaging, a process comprising the step of applyingwax or a blend of wax and thermoplastic resin to the corrugating mediumprior to corrugating, the step of corrugating the corrugating medium,the step of applying wax or a blend of wax and thermoplastic resin to atleast one of the liners, the step of applying an adhesive formulationbetween the liners and the corrugated medium, and the step of bondingthe liners and corrugating medium together with heat and pressure,wherein the corrugating medium is moisture conditioned before and afterthe wax or blend of wax and thermoplastic resin is applied to it.

References Cited UNITED STATES PATENTS 1,592,824 7/1926 Fairchild.1,856,282 5/1932 Holy 22934 2,099,936 11/ 1937 Kieckhefer. 2,418,963 4/1947 Anderson 22937 2,809,775 10/1957 White 22934 2,828,240 3/ 1958Couch et al. 2,912,152 11/1959 White. 2,939,624 6/1960 Wilson 22934 XJOSEPH R. LECLAIR, Primary Examiner. GEORGE O. RALSTON, Examiner.

UNITED STATES PATENT OFFICE Certificate Patent No. 3,366,496 PatentedJanuary 30, 1968 Thomas C. Bomar, William S. McDonald, and Hugh B.Johnson Application having been made b Thomas C. Bomar, William S.McDonald, and Hugh B. Johnson, the inventors name in the patent aboveidentified, and International Paper Company, New York, N.Y., acorporation of New York, the assignee, for the issuance of a certificateunder the provisions of Title 35, Section 256, of the United StatesCode, deleting the name of Thomas C. Bomar as a joint inventor, and ashowing and proof of facts satisfying the requirements of the saidsection having been submitted, it is this 18th day of December 1973,certified that the name of said Thomas C. Bomar is hereby deleted fromthe said patent as a joint inventor with the said William S. Mc- Donaldand Hugh B. Johnson.

FRED W. SHERLING Associate Solicitor.

1. IN THE MANUFACTURE OF CORRUGATED PAPERBOARD CONSISTING OF ACORRUGATED MEDIUM SANDWICHED BETWEEN AN INNER AND AN OUTER LINER ANDADAPTED TO BE CONVERTED INTO PACKAGING, A PROCESS COMPRISING THE STEP OFAPPLYING WAX OR A BLEND OF WAX AND THERMOPLASTIC RESIN TO THECORRUGATING MEDIUM PRIOR TO CORRUGATING, THE STEP OF CORRUGATING THECORRUGATING MEDIUM, THE STEP OF APPLYING AN ADHESIVE FORMULATION BETWEENTHE LINERS AND THE CORRUGATED MEDIUM, AND THE STEP OF BONDING THE LINERSAND CORRUGATED MEDIUM TOGETHER WITH HEAT AND PRESSURE, WHEREIN THECORRUGATING MEDIUM IS MOISTURE CONDITIONED BEFORE AND AFTER THE WAX ORBLEND OF WAX AND THERMOPLASTIC RESIN IS APPLIED TO IT.